fix: Use strtoull so so that 32 bits values are handled correctly

gcc/rust/ChangeLog:

	* lex/rust-lex.cc (Lexer::parse_non_decimal_int_literal): strtoull insted strtol

Signed-off-by: Mohamed Ali <mohmedali1462005@gmail.com>

Author: moabo3li

gcc/rust/lex/rust-lex.cc

@@ -2271,7 +2271,11 @@ Lexer::parse_non_decimal_int_literal (location_t loc, IsDigitFunc is_digit_func,
     }
 
   // convert value to decimal representation
-  long dec_num = std::strtol (existent_str.c_str (), nullptr, base);
+  // Use strtoull so that values like 0xFFFFFFFF are handled correctly on
+  // 32-bit hosts where |long| is only 32 bits and strtol would clamp to
+  // LONG_MAX (0x7FFFFFFF) instead of preserving the full unsigned value.
+  unsigned long long dec_num
+    = std::strtoull (existent_str.c_str (), nullptr, base);
 
   existent_str = std::to_string (dec_num);